Ginsenosides are primary active ingredients of ginseng, in which ginsenoside C-K belongs to a diol-type ginsenoside, and is not present in natural ginseng. Ginsenoside C-K is the major degradation product of other diol-type ginsenosides in human intestinal tract, which is indeed the entity that is absorbed and effects in the human body. Ginsenoside C-K not only has favorable activities in the aspects including anti-tumor, anti-inflammation, anti-allergy, liver protection and the like, but also plays a good role in regulation of both nervous system and immune system.
At present, reference 1 (Studies on the preparation, crystal structure and bioactivity of ginsenoside compound K, Journal of Asian Natural Products Research, 2006, 8(6), 519-527) has reported a crystal form of ginsenoside C-K, which is designated as crystal form G. It has been reported that the crystal form is a dihydrate of ginsenoside C-K, which belongs to the monoclinic system and has the following cell parameters: a=15.992(3) Å, b=11.960(19) Å, c=20.127(3) Å, α=90°, β=101.85°, γ=90°, V=3767.5(11)A3, and Z=4, in which the solvent system used consists of acetonitrile and water.
Generally, for an active pharmaceutical ingredient, the bioavailability may vary due to different crystal forms. Furthermore, physicochemical properties, including stability, flowability and compressibility may also be different, which will have certain influence on its applications. The crystal form D and crystal form H of ginsenoside C-K provided in the present invention have better stability than the existing crystal form G.